Part 1 of this interview introduced us to Brian Bainbridge who is the Ecological Restoration Planner at Merri Creek Management Committee. Today, we continue our chat and learn more about staged weed removal.
Can you give me an example of where you have staged your weed removal because the native animals were using the weeds as habitat?
Yes, we have a site in Fawkner called ‘Manna Gum’ on the western bank of the Merri Creek. This is only one of two sites in all of Moreland City Council area with a remnant Manna Gum. Back in the 1980s, local friends groups planted some native trees on the escarpment, including Swamp Gum, Yellow Gum and Red Gum. We have the beautiful old Manna Gum and some other remnant vegetation, but under those we had a massive quantity of Blackberry, Briar, Hawthorn, Gorse and Broom. In that understorey of dense shrubbery we also realised we had Blue Wrens and lots of other little bush birds that were persisting and using that as habitat.
How did you tackle all the woody weeds without impacting the bush birds?
In the early 2000s resources became available to do some restoration work on this site through a Parks Victoria community grant. We initially burnt the middle third of the site and began the treatment of the Blackberry on that third, and the rest was left as a bit of a weedscape. On either side there was quite an extensive patch of Boxthorns and Blackberry where the Blue Wrens and other birds could remain.
Why did you burn the site?
We used the burn to remove all the weedy biomass and to make the area suitable for spraying. We knew that on the ground layer we had remnant vegetation. After that burn we had a lot of Senecio hispidulis (Rough Fireweed) and quite a number of other native grasses coming up, and we had Maidenhair Fern, as well as the rare Carex incomitata (Hillside Sedge). We didn’t want to blast the whole thing with a general herbicide and to be able to do that we really needed to just be treating regrowth that was only a foot high or so.
What kind of follow up did you do?
In the early 2000s this site became part of Moreland Council’s ongoing maintenance commitment, so we revisited the site at least every 3-4 months, which meant that we could keep an eye on if things regrow. We never trust we’ve got the Blackberry treated until at least two years of revisits. Some of the techniques we used to control the Blackberry include cut and paint, drill and fill, but our main technique was spraying the re-growth of the Blackberry with a herbicide like metsulfuron-methyl. Using drill and fill on Hawthorns and other large woody weeds is a great way to retain shrub ‘skeletons’ which can be a really important habitat feature. You can then grow a Clematis or other climbers up it, or under plant with Tree Violets or other shrubs.
Did you then plant into the area?
We kept our ground-storey species plantings to areas that didn’t have Blackberry regrowth. It is also feasible to plant guarded trees and shrubs and then treat the Blackberry in between as long as you had a pretty good hit at the beginning, and where you only have a small number of regrowth points.
In 2001 we planted 1,500 plants into that area, which included Lightwood and Black Wattle and Sheoak, but also large quantities of the middle storey shrubbery. We were trying to re-establish some of that middle storey, so that birds could move back into that area.
Did you then move onto the other weedy patches?
Yes we did. In 2007 we had funding from an Environment Protection Authority alternative sentencing scheme to start the Black and Blue Project, where we went and knocked out more of the Blackberry, more of the Broom, more of the Boxthorns, and we planted another 500 trees and shrubs. So we were augmenting and making the indigenous vegetation patch larger each time. We were consciously trying to make thickets this time to ensure that within a few years the shrubs would tangle together and make good habitat for bird life.
Did the birds start to use the plantings that replaced the weeds?
Yes, in the last 6 years a Friends of Merri Creek quarterly bird watch has added many new species records to the Merri Creek, including woodland birds from the Manna Gum site. We have noticed some really interesting species coming into the site as a result of all the plantings we’ve done. We began to see things like Red-capped Robins a few years ago, we’ve seen White-winged Trillers, Spiny-cheeked Honeyeaters and a few years ago we even saw a Western Gerygone. The whole Manna Gum site is only a couple of hectares, but it’s next to a native grassland – the largest remnant grassland in Moreland City Council, and at the bottom of the escarpment you have the Merri Creek that has some riparian habitat. This area has became a real hotspot for biodiversity and I think it’s because it is the meeting point of different habitat types.
Seeing these species move in inspired us to put in another grant, to create a third expansion, which we called ‘Habitat Heroes’. This was funded by the Helen Macpherson Smith Trust. And so we removed the last remaining Boxthorn and Blackberries. Even though bush birds were still using the weeds as habitat, we could see they now had lots of habitat to move into, and removing the last Blackberries and Boxthorns wasn’t going remove all the habitat from the site.
It was only this year we had a groomer come in and remove the last extensive patch of Blackberry. A groomer is a machine that can mulch large areas of large woody weeds, such as Blackberry, Gorse and Boxthorn. We had already sprayed the Blackberry and so they just groomed down the dead stuff. The grooming alone doesn’t kill the Blackberry, as it will re-sprout from the roots. Now we’re treating the regrowth. This year we also planted another several hundred trees and shrubs with the community, extending the woodland/shrubland habitat by another hectare, and we’re hoping to see even more birds move in.
Just in the last few weeks we’ve seen a Rufous Whistler at the site, which had just been a transitory bird and we’d only hear the call for just a few days each year. But this year it has spent several weeks calling and trying to set up a territory. This year Golden Whistlers have been hanging out at Manna Gum as part of their winter territory. Again, they had been a bird of passage in previous years, but now they have enough habitat to hang out the whole of winter.
Back in 2002 I moved into a house just 50 meters away from this site and that has meant that I’ve had a ringside seat to watch all of these changes happen over the last 13 years. It’s been like a 24 hour nature channel; sitting on the back porch I could see all of these changes and I could hear all of the birds as they moved through the landscape.
That sounds like some great outcomes. Have you got any tips for anyone who wants to do staged weed removal?
Back in 1993 there was a big flora and fauna survey of Merri Creek. For many years our Friends of Merri Creek members and MCMC have wanted to see that baseline data replicated, but that only began to happen with quarterly bird surveys which started in 2009, conducted by Friends of Merri Creek in conjunction with Birds Australia (now Birdlife). I volunteered to lead a bird watch and incorporated a walk through the Manna Gum site as part of one of these three monthly bird visits. This has been continuing on right until now, so there’s about 6 years of data of birdwatchers running through the site in each season.
So there was unfortunately a gap of 16 years, between 1993 and 2009 where we weren’t methodically collecting data on flora and fauna, and we missed opportunities to document lots and lots of really amazing changes.
I would definitely recommend collecting some baseline flora and fauna data and do ongoing monitoring every year, so you can track some of those changes when you’re transforming a weedy landscape to an indigenous one.
I did a back-of-the-envelope analysis and compared the 1993 bird list to the 2015 bird list. I found that there’s an additional 60 species now using the Merri Creek and at least 30 of those species were definitely coming in as a result of improvements in the habitat.
I also think it’s worth making sure you step back and have a look at your site from different angles to recognise if you need to stage it. Aerial photos are a great way to look at the scale and the context of your site.
If you already have some adjoining habitat, and the weeds are expendable, you can go hell-for-leather with removal. But if they have some value as habitat, some forward planning is needed.
We’ve always anticipated that maybe in a year or two we’ll try for another grant and stage the work in that way too. You don’t have to think that you have to get everything done in your current projects.
What kind of baseline monitoring do you recommend?
One of the things with monitoring is not to get hung up on the amazing science of monitoring, you can very quickly lose momentum and heart trying to apply a monitoring program that’s too detailed.
There are a number of guides out there that try to simplify monitoring. The Friends of Merri Creek have the assistance of Birdlife in setting up their bird monitoring program. Birdlife have a standard 20 minute and 2ha searches, which I really recommend doing that rather than reinventing survey techniques.
Bird data is really magnificent for trying to interpret what’s going on in the landscape; you can look at any of those species and work out why that species is there. What are they eating? Which habitats do they live in? Which other species do they interact with?
We know that we have three different cuckoos in manna gum because there are so many Blue Wrens and other small birds – the cuckoos can lay their eggs in their nests. We’ve also had hundreds of Silvereyes this winter because we had a big year of Tree Violet berries.
Many of these projects use volunteers for tree and shrub plantings. Have you got any tips for increasing community engagement in these types of projects?
For years we struggled to attract the local community to the Fawkner stretch of the creek. We were just doing letter drops for the local area, putting the posters up in the library, sports centre or local shops. But in the last couple of years we’ve made really strong relationships with the local community house and some of the parenting groups, as well as using social media, and we’ve had 70-100 people coming to the last two planting groups.
So what changed?
I’m a local myself to the Fawkner area and I found being a local and being a part of the community house, I could make some much more personal contacts. So my wife and I started to invite people individually, as they recognised us as part of their community, and they’ve been much more interested in coming on board.
We’ve have a large and energetic Muslim community in Fawkner who we are keen to engage with. Recently a volunteer has been helping run our barbecues to make sure it’s Halal. Having someone from the Muslim community come on board has made people feel more confident to come along and make use of the free barbecue.
We also have a lot of young families in the area and building connections with the parenting group has been a major part of getting people involved. It’s the parents in particular who want to bring their kids along. Having these planting events is a great way to get the community engaged with the conservation work that has been happening here for the last 25 years.
Thank you for your time.
You can learn more about the Merri Creek Management Committee on their website: http://www.mcmc.org.au/